Azo dyestuffs



Patented Nov. I2, 1940 England, assigner to Imperial ChemicalIndus-f" 1W" triesiLimited; a corporation of Great Britain No` Drawing. Application March 29, 103.9, Serial N0. '264,845 InGreat lii'tilll.Alllil` 4, 1938 i '7` Claims. (Cl. 2604205) Thisinventicn relatesto new blue monazo dyestuffs, and to` methods oh, vmanufacturing the same.` Y y i In British specication No. 430,079 there is 5" described a process for the manufacture of water-soluble azo dyestuffs suitable for the dyeing and printing `of acetate artiiicial silk and other materials, which comprises coupling diazotized 6-chloro-.2:Ll-dinitroaniline orv diazotizedv 6-broor N-alkyl-N-sulphatoethyl derivative of an amine of ,benzene which is adapted toV couple in the para position` to the amino group and in which the, lterm alkyl signies methyl, ethyl,

DTODyI, or butyl.

It is among the objects of thepresent inven# tion to provide monazo dyestuifsv suitable for printing and dyeing acetate articial silk which zu havev good solubility, washing fastness, dischargeability and improved fastness` to light over dyes having somewhat .similarstructures.v Another object of the invention is to provide dyes having such improved light fastness in shades which a are bluer than other dyes having somewhat similar structures.

According to the present invention `we manufacture new water-soluble dyestuffs suitable for the dyeingor printing of cellulose acetate arti- 30 cial silk by combining, diazotized 6chloro, or

' G-Abromo-Z:l-dinitroaniline` with a coupiing component represented 4by the Kformula CHI in which R1 is alkyl (methyl tobutyl) and4 R2 n is a sulphatoethyl group. Alternatively, and also according tothe present inventiomwe manufacture thenew dyestuls byitreating the waterinsol'uble .dyestuffs obtained by combining Vdia zotized 6-chloro or Gy-bromo-'Z:fledinitroaniline with a coupling `component ofithe general formula n 55 wherein R1 isfthe` same as before and R3 is a `shade thandyestuffs' which arefsomewhatsimihydroxyethyl group, with an agent adapted to give their sulphuric esters,as for example sulphuric acid.

'I'he-dyestuisofthe` present 'invention have veryjgood solubility in hot'water; `goodfast- 5- nes's properties and are dischargeable. `They are` eminently suitable for the printing "of'face'tate articial silk. y

Moreover, they are valuable for the dyeing of wool, natural silk, tin-weighted-silk and leather. 10"? They yield colourations on acetatev articial silk which are faster to light than those given by the dyestuffs of the above-mentioned specification which dye in Tsimilar shades and are bluer in4 lar inv constitutionbutdo not have halogen in theazo component. l; w The Vinvention `is illustrated; but" not limited,

by the. following'examples inr which the "parts 2o areby weight' e 619 fparts -ofaSodiumnitrite rac-idea to 15o no solid remains. nitroaniline` are'added to the solution so-obtained with .stirringI in 11/1--2 hours." After; stirring for a" short time longer theresulting solution isheated to504-5`5? C. and kept atthattemperaturefor 2 hours. Itisthen icoled to A20`25"C;,` and addedfsl'owly.withi stirring to solution; (con' taining ic`e)= of 130:9 parts of the sodium `salt `of Nnbutyl-Nsulphatoethyl-nfi-toluidine. (which may be also called'N-n-butyl-N-'hydroxyethylter containing 13.6 parts of sodium acetate. Ice is addedl from tir'nftotirne to keep the tem! perature4 of the conplingirnedium at or' below 0 0.,- and 40% `adueous sodiumhydroxid'es'olu' 40 tion isV gradually addedv at such a ratethat the coupling medium is ,kepf just acid to Congo red paper'. "V `When all' the svulph'uric acid -solrutionhas been addedthe suspension' `of, the 'new' dyestufi` so-obtainedjis made alkaline with sodium hy- 45 droxide, stirred for somefftime to complete the conversion loflfthey dy'estuffjinto its 4sodium salt and then`t,her dyestuiff` is ltered oftfanddried. If necessary, the wetdyestuffspastecanbelixf iviated with water or 5% aqueous sodium' chloride 50, solution to remove adhering sodium sulphate before drying. f

The new dvestuifk forms 1 a. dark brown powder which'dis'solves inwhot` waterfwith a bluish-violet color and inconcentratedsulphuric acid A.with 55 i y y dyes acetate artificial silk in similar bluish-violety a yellowish-red color. It dyes acetate artificial silk in bluish-violet shades of very good light fastness from a neutral or alkaline dyebath containing 1% of sodium chloride. The colorations are readily dischargeable. It is also eminently suitable for printing acetate artificial silk.

The compound is' represented by the formula If in the above example instead of 21.8 parts of 6-chloro-2:4-dinitroaniline there are used 26.2 parts of 6-bromo-2:4dinitroaniline av dyestui of similar improved properties is obtained which shades of good fastness properties and good dischargeability.

Example 2 43.5 parts of the water-insoluble monoazo compound v6-chloro-2:4-nitroani1ine N-nbutyl-N-IS- hydroxyethyl-m-toluidine which is represented by the formula.

are ground to a powder and added in small portions to 200 parts of concentrated sulphuric acid at 15-25 C., with stirring. Stirring is continued until sulphation is complete. The latter is determined by adding a small test-portion of the sulphuric acid solution to ice, ltering olf the precipitated product to remove the acid liquor and resuspending it in water. The suspension is then made alkaline with sufcient sodium carbonate to form the sodium salt of the acid. If, on warming, the product passes completely into solution, then sulphation is complete.

When sulphation is complete the resulting sulphuric acid solution is'poured on toice and the new dyestuff which is precipitated is filtered ofi. resuspended in 500 parts of Water, 25 parts of sodium chloride are added, and the suspension made alkaline with aqueous sodium hydroxide solution to convert the dyestufl into its sodium salt.v The latter is then filtered 01T, washed with a little 5% aqueous sodium chloride solution and dried. 1

The resulting dyestuff possesses-similarreactions, shade, dyeing and `fastness properties to those given by the rst dyestuff of Example 1 and is believed to be identical in constitution with Example 21.8V parts of 6chloro2z4dinitroaniline are diazotized by themethod described in Example 1 and the diam-compound so-obtained coupled with 28.1 parts of the sodium salt of N-ethyl-N-sulphatoethyl-m-toluidine by they procedure described in Example 1 for N-n-butyl-N-sulphatoethyl-m-toluidine. The new dyestufi is isolated in a similar manner to that for the dyestuil of Example 1. It dyes acetate artificial silk in bluish-violet shades which are a little redder than those obtained with the dyestuis of Example 1 and which have vsimilar properties as regards fastness and dischargeability. f

Example 4 26.2 parts of 6-bromo2:4dinitroaniline are di- 'azotized by the method described in Example 1 for 6-chloro-2z4-dinitroaniline and coupled with 29.5 parts of the `sodium salt of N-isopropyl-N- sulphatoethyl-m-toluidine by the procedure described in Example 1 for N-n-butyl-N-sulphatoethyl-m-toluidineL The dyestui is isolated in the form of itssodium salt by the method described for the dyestuis of Example 1. It dyes acetate artiiicial silk from a neutral dyebath containing 1% of sodium chloride in bluish-violetshades of good fastness properties and dischargeability.

Instead of the N-alkyl-N-lsulfatoethyl-m-toluidines or the N-n-alkyl-n--hydroxyethyl-mtoluidines, any of the corresponding tertiary meta toluidines can be used in which alkyl is a branched or straight chain alkyl group having one to four carbons, such as'those in which alkyl is methyl, propyl or isobutyl. In forming the soluble products of the sulfato compoundsl described, any alkali metal or ammonium compound capable of forming an alkali metal salt can be used instead of sodium hydroxide, such as sodium carbonate, potassium hydroxde or ammonium hydroxide.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is:

1. A compound represented bythe formula X C Hs l I C :H40 .S 0 aY NO2 in which X is one of a group consisting of chloro and bromo, R is one o-f a group consisting of straight and branchedchain alkyl radicals having 1 to 4 carbons, and Y is one of a group consisting of alkali metals and ammonia.

2. A compound represented by the formula y C1 CH3 l l /R l l 1 o H oso Y l .Noi 2 3 in which R is one of a group `consisting' of straight and branched chain alkyl radicals having oneto four carbons, and Y'is'one of a group consisting of alkali metals and ammonia.

3. The compound in' accordance with'claim 2 in which R is butyl and Y is sodium.

4. The compound in accordance with claim 2 in which R is ethyl and Y is sodium.

5. The compound in accordance with claim 2 in which R is isopropyl and Y is sodium.

6. Process in the manufacture of new watersoluble dyestufi's suitable for dyeing and printing acetate artificial silk, which comprises treatingthe water-insoluble dyestuffs, obtained by coupling one of a group consisting of diazotized 6chloro and 6-brorno-2:4-'dinitroaniline with a coupling component of the general formula in which R1 is one of a group consisting of straight and branched chain alkyl radicals having one to four carbons and R3 is hydroxy ethyl, with an agent adapted to give the sulphuric esters `of said compounds.

7. The process which comprises adding in small portions to an excess of concentrated sulfurie acid a powder of `an insoluble monazo compound represented by the formula in which X is one of a group consisting of chloro and bromo and alkyl is one of a group consisting of straight and branched chain alkyl radicals having one to four carbons; agitating the mixture at 15 to 25 C. and sulfating until 'a product is formed which is insoluble in water but whose sodium salt is soluble in Warm water.

ARTHUR HOWARD KNIGHT.

CERTIFICATE OF CORRECTION. Patent No. 2,220,965. November 12, 191m.

ARTHUR HOWARD KNIGHT. l

It is hereby oer'tfied that error appears in the printed specificati-ot; of the above numbered patent requiring correction as follows: Page 1, first column, line 2, for "oh" read -of; page 2, second column, line T1, claim 6, for "in" read` -for-; and that the said' Letters Patent shouId be read with this correction theren`that the same may conform to the record of the oase in the Patent Office'.

' signed and Sealed this4 17th 'day of December, A. D. 191m).

Henry Van Arsdale (Seal) otng Commissioner of: Patents. 

